Photographic color diffusion transfer processes and elements



United States Patent 3,462,266 PHOTOGRAPHIC COLOR DIFFUSION TRANSFER PROCESSES AND ELEMENTS Paul H. Stewart, Rochester, N.Y., assignor to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey No Drawing. Filed Sept. 5, 1967, Ser. No. 665,296 Int. Cl. G03c 5/54, 5/30 U.S. C]. 96-29 16 Claims ABSTRACT OF THE DISCLQSURE Oxazines and bisoxazines which are cleaved to hydroquinones under alkaline conditions, are useful auxiliary developer precursors in dye developer image transfer systems. Novel hydroxyalkylaminoalkylhydroquinone auxiliary developers are provided.

This invention relates to the art of photography and more particularly, to image transfer systems and materials adapted for use in such systems.

A diffusion transfer color process has been described in a number of patents, including U.S. Patent 3,146,102, wherein photographic elements containing silver halide emulsion layers and layers containing diifusible dye developers (dyes having a silver halide developing function) are exposed to record the latent image in the silver halide and then treated with an alkaline processing composition which permeates the emulsion layer and layers containing the dye developers which then develop the latent images to silver images. At the same time oxidation products of the dye developers are formed in situ with the silver images and which are relatively nondiifusing in the colloid vehicle of the layers.

The nonditfusing character of the oxidized dye developers is apparently due at least in part to a decrease in solubility in the alkaline processing liquid, and may also be due to a hardening effect of the oxidized developer upon the colloid vehicles of the layers which retards the diffusion of the oxidized dye developers. The residual unoxidized dye developers remaining in the layers in imagewise distribution are transferred by diffusion to a superposed reception element substantially to the exclusion of the silver image and oxidized dye developer to provide a positive dye image.

When an element containing differentially sensitized silver halide emulsion layers is used and subtractively colored dye developers are present in or contiguous to the respective emulsion layers, upon treatment with the processing liquid the dye developers are oxidized and rendered nondilfusing in the developed regions of the layers and the residual dye developer images in the positive regions are transferred by diffusion and in register to the reception element to provide a multicolor reproduction.

As is apparent, the success of the process depends in part upon the extent to which the dye developers in the exposed (negative) regions of the emulsion layers have been rendered substantially nondiffusing in the development reaction. Thus, if a quantity of unoxidized dye developer remains in a fully exposed negative region corresponding to the highlights of the subject, it will be transferred to the reception layer along with the unreacted dye developer in the positive regions and appears as high minimum density on the resultant color print.

Typical dye developers such as 1,4-bis[[i-(2,5-dihydroxyphenyl)ethylamino]anthraquinone, are relatively weak silver halide developing agents even when used at the comparatively high pH of the order of 12 required in the process and do not so rapidly develop silver halide "ice emulsions as to take full advantage of sensitometric prop erties of the emulsions and to obtain dye images having a full scale of density and contrast expected with other developing agents. As a result, color prints obtained in the processes may exhibit an undesirable high minimum density in the highlight regions, low color saturation, contrast and density and the color separation is poor.

These undesirable effects are partially due to the inefficiency and lack of discrimination of the dye developers as silver halide developing agents. Various compounds have been proposed for employment as auxiliary silver halide developing agents, which compounds increase the quality of the resultant color print. The use of such compounds improves print densities, color saturation, and contrast to some degree. However, attempts to improve the color prints by employment of the auxiliary silver halide developers have resulted in undesirable increases in minimum densities. Additionally, certain of the proposed auxiliary developing agents result in an objectionable yellow stain in the final color print. Other proposed auxiliary developing agents have had poor resistance to aerial oxidation.

It is therefore an object of this invention to provide photographic products that are suitable for the production of excellent dye developer images.

A further object of the invention is to provide a process for the production of dye developer images having low minimum densities.

Another object of this invention is to provide photographic products that are suitable for the production of color prints having excellent contrast. Other objects of this invention will be apparent from this disclosure and the appended claims.

In accordance with one embodiment of this invention, in the processing of an exposed photosensitive element comprising a support, at least one light-sensitive silver halide emulsion layer and a dye developer which is both a silver halide developing agent and a dye contiguous to the silver halide of the emulsion layer, which processing is effected by treating said photosensitive element with an alkaline liquid, developing a latent image in the regions of exposure of the silver halide emulsion layer and thereby immobilizing dye developer in the regions of exposure, dye developer in undeveloped regions diffusing imagewise in register to a dye developer reception layer: the improvement is provided which comprises initiating said processing in the presence of a substantially colorless, auxiliary silver halide developing agent precursor selected from the group consisting of oxazines and bisoxazines capable of forming substantially colorless, alkali-soluble hydroquinones in said alkaline liquid.

In still another embodiment of this invention, in the processing of an exposed photosensitive element comprising a support, at least one light-sensitive silver halide emulsion layer and a dye developer which is both a silver halide developing agent and a dye contiguous to the silver halide of the silver halide emulsion layer, which process ing is effected by treating said photosensitive element with an alkaline liquid, developing a latent image in the regions of exposure of the silver halide emulsion layer and thereby immobilizing the dye developer in the regions of exposure, dye developer in undeveloped regions diffusing imagewise in register to a dye developer reception layer: the improvement is provided which comprises effecting said processing in the presence of a substantially colorless, alkali-soluble auxiliary silver halide developing agent which is a hydroquinone containing at least one hydroxyalkylaminoalkyl substituent. Preferred hydroquinones of this class have lower alkyl groups, such as hydroxymethylaminoethyl, hydroxyethylaminoethyl, hydroxypropylaminopropyl or hydroxybutylaminobutyl. Advantageously, the hydroquinone contains one or two of such groups, preferably in the 2, the 2,3- or the 2,5-positions. Typical useful auxiliary developers of this invention include a Z-hydroxymethylaminomethylhydroquinone; a 2,3-bis[hydroxymethylaminomethyl]hydroquinone; and, a 2,5 -bis [hydroxymethylaminomethyl] hydroquinone.

In accordance with another embodiment of this invention, a multilayered photographic product is provided comprising a photosensitive element, which comprises a support layer; at least one light-sensitive silver halide emulsion layer, a dye developenwhich is both a silver halide developing agent and a dye contiguous to the silver halide of the silver halide emulsion layer; and, a substantially colorless, auxiliary silver halide developing agent precursor comprising either an oxazine or a bisoxazine, which is capable of forming a substantially colorless, alkalisoluble hydroquinone incorporated in one of the layers of the photographic product.

In another embodiment of this invention, a multilayered photographic product is provided comprising a photosensitive element, which comprises a support layer; at least one light-sensitive silver halide emulsion layer; and, a dye developer which is both a silver halide developing agent and a dye contiguous to the silver halide of said silver halide emulsion layer; and, incorporated in one of the layers of said photographic product, a substantially colorless, alkali-soluble auxiliary silver halide developing agent which is a hydroquinone containing at least one hydroxyalkylaminoalkyl group, such as those described above.

It has been surprisingly found that oxazines and bisoxazines, which are not themselves developing agents, are highly desirable precursors for auxiliary silver halide developing agents when they are provided in the aforesaid dye developer diffusion transfer systems. The resulting color prints have low minimum densities. In addition,

these auxiliary developing agents have good resistance to aerial oxidation.

The auxiliary developer precursors of the present invention are oxazines and bisoxazines capable of being cleaved with alkali to form substantially colorless, alkalisoluble hydroquinones. Suitable precursors include those compounds having the structural formula IILT 1 14 ,oH -1yoHr- R1 in which R represents any of the groups represented by R.

One class of compounds encompassed by the aforesaid general formula and which form substantially colorless alkali-soluble hydroquinone auxiliary developers may be represented by the formula 2 op-orr N l R wherein R is defined as before. Representative compounds include:

3-hydroxyethyl-6-hydroxy-2,3,4-trihydro-1-oxa-3- azanaphthalene,

3-ethyl-6-hydroxy-2,3 ,4-trihydro-1-oxa-3- azanaphthalene,

3-isopropyl-6-hydroxy2,3 ,4-trihydro-1-oxa-3- azanaphthalene,

3-allyl-6-hydroxy-2,3 ,4-trihydro- 1-oxa-3- azanaphthalene,

3-phenyl-6-hyd-roxy-2,3,4-trihydro-1-oxa-3- azanaphthalene,

3-benzyl-6-hydroxy-2,3,4trihydro-l-oxa-3- azanaphthalene,

6-hydroxy-2,3 ,4-trihydro-1-oxa-3-azanaphthalene,

3-N,N-dimethylaminoethyl-6-hydroxy-2,3 ,4-trihydro-1- oxa-3-azanaphthal ene,

3-cyclohexyl-6-hydroxy-2,3 ,4-trihydro-1-oxa-3- azanaphthalene.

A second class of compounds encompassed by the general formula (1), above, may be represented by the formula:

wherein R and R are defined as before. Specific examples of this class of compound include:

3,7-'bis(hydroxyethyl)-2,3,4,6,7,8-hexahydro-1,5-dioxa- 3,7-diazaanthracene,

3,7-dimethyl-2,3,4,6,7,8-hexahydro- 1,5 -dioxa-3,7

diazaanthracene,

3,7-dibenzyl-2,3,4,6,7,8-hexahydrol,2-dioxa-3,7-

diazaanthracene,

3,7-diallyl-2,3,4, 6,7,8-hexahydrol,2-dioxa-3,7-

diazaanthracene,

3,7-dicyclohexyl-2,3,4,6,7,8-hexahydro-1,2-dioxa-3,7-

diazaanthracene,

3,7-bis(N,N-dimethylaminoethyl)-2,3,4,6,7,8-hexahydro- 1,S-dioxa-3,7-diazaanthracene,

3,7-diphenyl-2,3,4,6,7,8-hexahydro-l ,5-dioxa-3,7-diazaanthracene,

2,3,4,6,7,8-hexahydro-l,5-dioxa-3,4-diazaanthracene.

Another class of compounds which are encompassed by the general Formula 1 may be represented by the formula:

wherein R and R are defined as before. Specific examples of this class of compounds include:

3,6-bis(hydroxyethyl)-2,3,4,5,6,7-hexahydro-1,8-dioxa- 3,6-diazaphenanthrene,

3,6-dimethyl-2,3 ,4,5,6,7-hexahydro-1,8-dioxa-3,6-

diazaphenanthrene,

3,6-diallyl-3,4,5,6,7-hexahydro-l,8-dioxa-3,6-diazaphenanthrene,

3,6diphenyl-2,3,4,5,6,7-hexahydro-l,8-dioxa-3,6-

diazaphenanthrene,

3,6-dibenzyl-2,3,4,5,6,7-hexahydro-1,8-dioxa-3,6-

diazaphenanthrene,

3,6-ditertiarybutyl-2,3,4,S,6,7-hexahydro-1,8-dioxa,3,6-

diazaphenanthrene,

3, 6-bis (N,N-dimethylaminoethyl -2,3,4,5,6,7-hexahydro- 1,8-dioxa-3 ,6-diazaphenanthrene,

2,3,4,5,6,7-hexahydro-1,8-dioxa-3,6-diazaphenanthrene.

The foregoing compounds may be prepared in any conventional manner. One suitable means is that described in an article by Fields et al. in the Journal of Organic Chemistry, volume 27, page 2740 [1962], which is hereby incorporated by reference.

The oxazine and bisoxazine auxiliary developer precursors of the 'present invention may be suitably provided in any of the layers of the photosensitive element, such as in an overcoating layer, a silver halide emulsion layer, dye developer layer, and/or in an interlayer. The precursor may also be provided in the reception sheet. When the auxiliary developer precursor is contacted by the alkaline processing solution, it is converted into a substantially colorless, alkali soluble hydroquinone derivative which has highly desirable properties as an auxiliary silver halide developing agent. The alkaline processing solution has a pH of at least 12, and preferably a pH of about 14. The precursors of the invention are cleaved to hydroquinones at such pH levels; however, lower pH will also serve to convert the precursors to hydroquinones. The reaction may be represented by the following equation in which the precursor is a bisoxazine of the phenanthrene variety [represented by Formula 4, above]:

As may be seen from the foregoing equation, the bisoxazine is cleaved to yield a 2,3bis(hydroxymethylaminomethyl)hydroquinone auxiliary silver halide developing agent by the reaction with an alkaline material. This same type of cleavage reaction occurs with each of the compounds encompassed by the broad general precursor formula previously described. In the case of the oxazine precursor of the present invention, the resulting auxiliary developer is a 2 hydroxymethylaminomethylhydroquinone:

HOCH2 IITCHI The bisoxazines of the anthracene variety are cleaved to yield a 2,5 bis(hydroxymethylaminomethyl)hydroquinone represented by the formula:

Specific examples of the hydroquinone auxiliary developing agents include, for example:

2 [N-hydroxymethyl-N-methylaminomethyl hydroquinone,

2 [N-hydroxym ethyl-N-hydroxyethylaminomethyl] hydroquinone,

2 Nhydroxyrnethyl-N-b enzylaminomethyl] hydroquinone,

2 [N-hydroxymethyl-N-phenylaminomethyl] hydroquinone,

2 [N-hydroxymethyl-N-cyclohexylaminomethyl] hydroquinone,

2 [N-hydroxymethylaminomethyl] hydroquinone,

2 [N-hydroxym ethyl-N- N,N-dimethylaminoethyl) aminomethyl] hydroquinone,

2,3 -bis[N-hydroxymethyl-N-methylarninomethyl1hydroquinone,

2,3 -bis [N-hydroxymethyl-N-hydroxyethylaminomethyl] hydroquinone,

2,3 -bis [N-hydroxymethyl-N-benzylaminomethyl] hydroquinone,

2,3-bis [N-hydroxymethyl-N-phenylaminomethyl]hydroquinone,

2,3 -bis [N-hydroxymethyl-N-cyclohexylaminomethyl] hydro quinone,

2,3 -bis [N-hydroxymethyl-N-allylaminomethyl] hydroquinone,

2,3-bis [N-hydroxymethylaminomethyl] hydroquinone,

2,5 -bis [N-hydroxymethyl-N-hydroxyethylaminome thyl] hydroquinone,

2,5 -bis [N-hydroxymethyl-N-methylaminomethyl] hydroquinone,

2,5 -bis [N-hydroxymethyl-N-b enzylaminomethyl] hydroquinon e,

2, 5 -bis [N-hydroxymethyl-N-allylaminomethyl] hydroquinone,

2,5 -bis [N-hydroxymethyl-N-phenylaminomethyl] hydroquinone,

2,5 -bis [N-hydroxymethyl-N-(N,N-dimethylamino) amino methyl] hydro quinone,

2, S-bis [N-hydroxymethylaminomethyl] hydro quinone.

The concentration of the auxiliary developing agent precursor employed in the photographic product of the present invention may be varied over a wide range. For example, suitable amounts of the precursor include between about 3 and about 500 milligrams or more of the oxazine or bisoxazine per square foot, preferably between about 10 and about milligrams per square foot, in one or more of the layers.

As previously mentioned, the auxiliary developing agent precursor may be placed in any of the layers of the photosensitive element and in the reception sheet. Likewise, if it is desired to employ the hydroxymethyl aminomethylhydroquinones in the photographic elements of the present invention, rather than their precursors, the auxiliary developers may be provided in any of the layers of the photosensitive element and reception sheet. However, the auxiliary developer may be also provided in the alkaline processing solution, if desired, which solution may be contained in a rupturable pod.

The hydroquinone derivative and their precursors may be provided in the photographic element in any suitable manner. Thus, the oxazine or bisoxazine may be dissolved in a solvent, such as a lower alcohol, and incorporated into aqueous gelatin solutions for coating onto the sensitive element. Alternatively, they may be added to gelatin solutions which are ball-milled to the proper crystal size. However, the auxiliary developers or their precursors are preferably dissolved in a low molecular weight waterinsoluble organic crystalloidal solvent which is permeable to the alkaline processing solutions and has a boiling point above about C. The resulting solution is then added to an aqueous gelatin solution which is then passed through a colloid mill until the desired degree of subdivision has been attained.

The solvent may be liquid at room temperature or a low melting point solid and may contain one or more polar groups such as hydroxyl, carboxylic acid, amide or ketone, although this is not a limiting factor. It should be inert toward the silver halide emulsions and substantially colorless so that it does not impart color to the print. In this respect, it is distinct from the dye developers containing hydroquinonyl group.

The preferred high boiling point solvents include alkyl esters of phthalic acid in which the alkyl radical preferably contains less than 6 carbon atoms, e.g., methyl phthalate, ethyl phthalate, propyl phthalate, n-butyl phthalate, di-n-butyl phthalate, n-amyl phthalate, isoarnyl phthalate, but dioctyl phthalate, esters of phosphoric acid, e.g., triphenyl phosphate, esters of phosphoric acid, e.g., triphenyl phosphate, tricresyl phosphate and diphenyl mono-p-tert, butyl phenyl phosphate may be used. Also, alkyl amides or acetanilides, e.g., diethyl lauramide, N- butylacetanilide, N-methyl-p-methyl acetanilide may be used. Also, alkyl amides or acetanilides, e.g., diethyl lauramide, N-butylacetanilide, N-methyl-p-methyl acetanilide may be used.

In a preferred method, the precursor or the auxiliary developer is dispersed in a layer of the sensitive material by means of a mixture of one of the above mentioned high boiling point solvents and either an auxiliary lower boiling point solvent or a solvent more soluble in water. The lower boiling point solvents are substantially waterinsoluble and have boiling points at least about 25 .C. below that of the higher boiling point solvents which allows the lower boiling point solvent to be vaporized from the coatings during drying leaving the hydroquinone derivative or its precursor dispersed therein in globules of the higher boiling point solvent. These solvents include, e.g., methyl, ethyl, propyl and butyl acetates, isopropyl acetate, ethyl propionate, sec.-butyl alcohol, carbon tetrachloride, chloroform, benzyl alcohol, 2,3- and 4-methylcyclohexanones, which are volatile solvents and can be removed by aid drying in the presence of the higher boiling point solvent. By use of such auxiliary lower boiling point solvents lower temperatures can be used to dissolve the hydroquinone derivatives or their precursors, resulting in less decomposition than when the higher boiling point solvent is used alone.

The solvent which may be used in admixture with the high boiling point solvents for subsequent removal by washing the dispersions, are more soluble in water than the high boiling point solvents and have solubility in water of at least 2 parts per 100 parts of water (parts by weight). Such solvents include methyl isobutyl ketone, 8- ethoxyethyl acetate, fl-butoxy-B-ethoxyethyl acetate, tetrahydrofurfuryl adipate, diethylene glycol monoacetates, methoxy triglycol acetate, acetonyl acetone, diacetone alcohol, ethylene glycol diethylene glycol, dipropylene glycol, 2,3- and 4-methyl cyclohexanones, ethylene glycol monomethylether acetate, diethylene glycol monobutylether, ethyleneglycol monobutyl ether, diethylene and glycolmonomethyl ether, cyclohexanone which may be used in conjunction with the high boiling point solvent diethyl lauramide, triethylphosphate, and ethyleneglycolmonomethyl ether. Methyl alcohol may be used as the auxiliary solvent with di-n-butyl phthalate. The auxiliary developer precursors can be applied to the surface of photosensitive element (negative) from an organic solvent, such as acetonitrile. They can also be present in other layers of the photosensitive element, such as interlayers, silver halide emulsion layers or dye developer layers. In addition, the precursors can be in the dye-developer reception layer. When the dye-developer reception layer is not integral with the photosensitive element, i.e., when it is coated on a separate support, the precursors hereof can be incorporated in various layers thereof, such as an overcoat layer, a spacer layer, mordant layer or acidic layer.

The dye developers which may be used in accordance with the present invention are well known in the photographic art. Such compounds function both as a silver halide developing agent and as a dye in photographic diffusion transfer systems. Dye developers are characterized as being relatively non-diffusible in colloid layers such as the hydrophilic organic colloids used in photographic emulsions at neutral pH, but are diffusible in the photographic elements in the presence of alkaline processing solutions. Generally, such dye developers are substantially insoluble in water, which property usually necessitates the use of organic solvents to incorporate the dye developers into the organic colloid layers of the photoelements. The dye developers are particularly characterized as containing both a chromophoric or dye moiety and at least one moiety having a silver halide developing agent function. Particularly useful dye developers are those wherein the chromophoric moiety is an azo or anthraquinone dye moiety and the silver halide developing moiety is a benzenoid moiety such as a hydroquinonyl moiety.

Representative dye developers of use in the dispersions of the invention have the general formula MN=ND in which M is an aromatic or heterocyclic ring or ring system such as a benzene, naphthalene, tetralin, anthracene, anthraquinone, pyrazole, quinoline, etc., ring which can be substituted with such groups as hydroxyl, amino, keto, nitro, alkoxy, aryloxy, acyl, alkylamido, alkylaryl, carboxamido, sulfonamido, carboxyl or sulfo groups. D represents a silver halide developing agent function to the dye developer such as a hydroquinonyl group which can be substituted with amino, alkylamino, alkyl, hydroxyl, alkoxyl or halogen groups.

Typical useful dye developers are described in US.

2 Patents 3,146,102, 3,161,506, as well as elsewhere in the patent literature, including: Australian 220,279; German 1,036,640; British 804,971 and 804,973-5; Belgian 554,935; French 1,168,292; and Canadian 577,021 and 579,038.

In the photographic elements of the invention, the dye developers are preferably incorporated in hydrophilic organic colloidal vehicles or carriers comprising the layers of the photographic element dissolved in high-boiling or crystalloidal solvents and dispersed in finely-divided droplets. Typical high-boiling, water-insoluble solvents that can be used to dissolved dye developers in preparing the dispersions of the invention are described in US. Patent 2,322,027.

The dye developers utilized in the photographic elements may also be incorporated into vehicles soluble in organic solvents which are also solvents for the dye developers. Likewise, other incorporating techniques for the dye developers such as ball-milling may be utilized.

The dye developers are positioned contiguous to the silver halide of the photographic silver halide emulsion layers of the present photographic elements. Such dye developers may be incorporated directly in the silver halide emulsions or preferably positioned in a sublayer contiguous to each silver halide emulsion layer. The contiguity of the dye developer 'with respect to the silver halide may take the form of a mixed packet system wherein the dye developer can be present in a matrix surrounding a particle or globule containing silver halide grains. The dye developers are preferably substantially complementary in color to the color of the light recorded or spectral sensitivity of the silver halide emulsions contiguous thereto.

A wide variety of diffusible onium compounds may be utilized in the photosensitive product of the present invention. Such onium compounds, that is, compounds that contain an organic cation, are diifusible in the hydrophilic organic colloids comprising the present photographic elements in the presence of alkaline processing compositions. Such onium compounds are typically quaternary ammonium compounds, quaternary phosphonium compounds or tertiary sulfonium compounds. A particularly useful class of onium compounds are heterocyclic quaternary arnmonium compounds that are capable of forming ditfusible methylene bases in alkaline processing compositions such as those described in US. Patent 3,146,102. In dye developer diffuser transfer systems, the onium compounds are preferably utilized in the alkaline processing composition, although the onium compounds may also be utilized in the reception sheet, or less desirably, in one or more layers of the light-sensitive element, or in at least two of such positions.

Water-soluble silver halide solvents may be employed in the alkaline processing compositions used in the dye developer transfer process of the invention, particularly in conjunction with onium compounds and colorless hydroquinone derivatives as described above, such addenda lending further improvement in color quality results. Preferred silver halide solvents are thiosulfates such as sodium, potassium and ammonium thiosulfate.

The silver halide emulsions utilized in preparing photographic or light-sensitive elements used in the present diffusion transfer systems can be any of the conventional negative-type, developing-out emulsions. Typical suitable silver halides include silver chloride, silver bromide, silver bromoiodide, silver chloroiodide, silver chlorobromoiodide and the like. Mixtures of more than one of such silver halides may also be utilized. In accordance with usual practice, such silver halide emulsions can contain spectral sensitizers, speed-increasing addenda, ha-rd eners, coating aids, plasticizers, antifoggants and the like conventional emulsion addenda.

In preparing such silver halide emulsions, as well as in preparing the various layers of photographic products used in the present difi'usion transfer process, including the layers containing the dye developers and colorless auxiliary developing agents or their precursors, mordantcontaining reception layers, interlayers, topcoat layers and the like, a wide variety of hydrophilic organic colloids may be utilized as the vehicle or carrier. Gelatin is preferably used as the hydrophilic colloid or carrier material water-soluble derivatives and copolymers, water-soluble copolymers such as polyacrylamide, immidized polyacrylamide, etc., and other water-soluble film-forming materials that form water-permeable coats such as colloidal albumin, water-soluble cellulose derivatives, etc., may be utilized in preparing the photographic elements. Compatible mixtures of two or more of such colloids can also be utilized.

The various layers utilized in preparing the difiusion transfer photographic elements used in the process of the invention may be coated on a wide variety of photographic supports. Typical supports include cellulose nitrate film, cellulose acetate film, polyvinyl acetal film, polystyrene film, polyethylene terephthalate film, polyethylene film, polypropylene film, pape-r, polyethylenecoated paper, polypropylene-coated paper, glass and the like.

Similarly, a wide variety of receiving sheets may be employed to receive the transfer images from the photographic elements. Typical reception layers for receiving sheets include such materials as linear polyamides, proteins such as gelatin, polyvinyl pyrrolidones, poly-4-vinyl pyridine, polyvinyl alcohol, polyvinyl salicylal, partially hydrolyzed polyvinyl acetate. methyl celluose, regenerated cellulose, or mixtures of such. These reception layers may be coated on a suitable support of the type described above for the light-sensitive elements of the invention and including transparent as well as opaque supports.

Receiving sheets that release acidic material such as that derived from an acidic polymer or other acidic compound at a controlled rate as are described in US. Patent 2,584,030 are particularly useful. Such acidic materials are typically positioned in layers on the receiving sheet below the dye developer reception layer, there suitably being a spacer layer between the acid layer and the mordanting layer to control the release of acidic material. Such acidic materials serve to neutralize residual portions of the alkaline activator on the receiving sheet.

A wide variety of nondilfusible cationic or base dyemordanting compounds can be used in liquid permeable reception layers including amines such as polymeric amines, quaternary ammonium compounds, quaternary phosphonium compounds and tertiary sulfonium compounds. Such mordants are nondiffusible in the alkaline processing composition and contain at least one hydrophobic ballast group. As mentioned above, the colorless hydroquinone derivatives or their precursors may be incorporated in the receiving sheets. The receiving sheets may also contain development arrestors such as mercaptoazoles and iodides.

Light-sensitive elements containing integral reception layers for dye developer images may also be utilized. Such integral reception layers can be coated beneath the emulsion and dye developer layers near the support. A stripping layer coated over the integral reception layer can be used to facilitate the removal of the over-coated layers after the diffusion of the dye developer images to the reception layer.

The processing compositions or activators used to initiate development of the exposed light-sensitive elements and cleavage of the auxiliary developing agent precursors in accordance with the invention are strongly alkaline. Such processing compositions generally have a pH of at least 12 or contain at least .01 N hydroxyl ion. Alkali metal hydroxides, such as sodium hydroxide, are advantageously used in the composition for imparting such high alkalinity. However, volatile amines such as diethyl amine can also be used, such amines having the advantage of being volatilized from the prints to leave no residue of alkali. The processing compositions are generally aqueous liquids or solutions, and when utilized in rupturable pods for in-camera processing such as described in US. Patent 2,435,717, generally contain thickening agents such as hydroxyethyl cellulose or carboxymethyl cellulose. Thickening processing compositions typically have viscosities of at least 5,000 cps. to 100,000 or even 200,000 cps.

Example 1 shows photosensitive elements of the type in which there is incorporated the auxiliary developing agent precursors in accordance with the invention.

EXAMPLE 1 A sensitive element is prepared by coating a subbed film support comprising cellulose acetate with suitably hardened gelatin layers as follows:

(1) Cyan dye developer layer.An aqueous gelatin containing the cyan dye developer 5,8-dihydroxy-1,4-bis 3-hydroquinonyl-ot-methyl) ethylamino] anthraquinone is dissolved in a mixture of N-n-butylacetanilide, 4-methyl cyclohexanone and dispersing agent Alkanol B. The mixture is passed through a colloid mill several times, coated on the subbed support and dried so as to volatilize the 4- methyl cyclohexanone.

(2) Red-sensitive emulsion layer.A gelatino silver bromoiodide emulsion layer, which is sensitized to the red region of the spectrum is coated upon the cyan dye developer layer.

(3) Interlayen-A gelatin interlayer is then coated on the red-sensitive emulsion layer.

(4) Magenta dye developer layer.An aqueous gelatin solution containing the magenta dye developer 2[p- (2,5'-dihydroxyphenethyl)phenylazo] 4 n propoxyl-naphthol is dissolved in a mixture of cyclohexanone, N- n-butylacetanilide and Alkanol B is passed through a colloid mill several times, coated on the interlayer and dried to volatilize the cyclohexanone.

(5) Green-sensitive emulsion layer.A green-sensitive silver bromoiodide emulsion is coated on the magenta layer.

(6) Interlayer.-A second gelatin interlayer is coated onto the green-sensitive emulsion layer.

(7) Yellow dye developer layer.An aqueous gelatin solution of the yellow dye developer, l-phenyl-3-N-n-hexylcarboxamido 4 [p 2',5' dihydroxyphenethyl)phenylazo]-5-pyrazolone, is dissolved in a mixture of ditetrahydrofurfuryl adipate, ethylene glycol monobenzyl ether, and Alkanol B, is passed through a colloid mill several times. The resulting dispersion is chilled to set it, Washed to remove ethylene glycol monobenzyl ether followed by coating upon the second interlayer and drying.

(8) Blue-sensitive emulsion layer.A blue-sentitive silver bromoiodide emulsion is coated onto the yellow dye developer layer.

(9) Overcoat layer.A final gelatin emulsion overcoat layer is provided on the foregoing layers.

Examples 2-7 show photosensitive elements, such as described in Example 1, which contain the precursors of the invention.

EXAMPLES 2-7 1 2 (IV) 3,6 diallyl 2,3,4,5,6,7 hexahydro 1,8 dioxa- 3,6-diazaphenanthrene A sample of the freshly coated film, as produced in Ex- CH2:OHCHN N GH2CH:CH ample 1, is placed on a vacuum plate in a horizontal posi- (V) 3 hydroxyethyl 6 hydroxy 2,3,4 trihydr tion and a control solution of acetonitrile is spread uni- 1-oxa-3-azanaphtalene formly over the coated film and the excess soltuion is drained ofi. Next, the treated negative is air dried in a vertical position, exposed imagewise on an Eastman 1B Sensitometer 1/50" to a 500 watt positive lamp plus a 4.08 NOH1CHBOH Corning filter and processed with a processing solution dis- The results are set forth in Table 2 below:

' TABLE 2 Neutral scale of print D. max. D. min Example Concentration, No. Compound Solvent lugs/ft! Red Green Blue Red Green Blue 2 Aeetonitrile. 1.21 1.80 1.90 .32 .61 .63 3 I ethanol... 44 1.18 1.78 1.90 .22 .40 .47 4 II do.. 44 1.12 1.68 1.87 .18 .27 .32 5 III Acetonitrile 35 1. 2a 1.78 1.98 .18 .28 .32 e IV do 43 1.18 1.74 1.88 .23 .48 .51 7 v Methanol 62 1.22 1.76 1. 90 .21 .33 .40

posed in a processing pod and having the composition set As may be seen upon viewing the print density values forthinTableIbelow: obtained, the minimum density is considerably reduced TABLE I in each instance that the auxiliary silver halide developing P t agent precursor is utilized as compared with the Example b i h 2 wherein no precursor is employed. In addition, each of d h l ll l (HEC) 3,6 the color prints which is produced in Examples 3 through potassium h d id 6,8 7 have less magenta and yellow stain than the control. Lithium hydroxide 0.2 Sodium thiosulfate pentahydrate 0.5 EXAMPLE 8 Y- Y Y- Y p For purposes of comparison, the procedure of the fore- Benzotriazole 2-0 going examples is repeated employing a bisoxazine which Zinc nitrate 0.4 is outside the scope of the present invention. l-benzyl-Z-picolinium bromide 3.4 Thus, an acetonitrile solution of 2,7-bis(hydroxyethyl)- The exposed film is processed at a gap of 004 inch 1,2,3,6,7,8-hexahydro-4,5-dioxa-2,7-diazaphenanthrene (corresponding to the thickness of the activator layer) for 40 a period of 60 seconds in contact with a color receiving sheet. The receiving sheet is a cellulose acetate butyrate subbed paper support carrying in the following order:

(1) A polymeric acid layer comprising a copolymer of HO-CH2CHz-NO 0-NOHgCH OH butyl acrylate (60%) and acrylic acid (40%) for pH control is prepared and coated onto the overcoat layer as before.

( Apolyvmyl alcohol P F layer, This compound yields a catechol derivative upon being A fnol'dant layer compnsmg P Y' Pyndme cleaved by the alkali in the processing solution. and P Y Y alcohol, and Testing of the resultant color print indicates that the A P y y alcohol Protectlve yer. catechol derivative of this example has no auxiliary de- The foregoing procedure is repeated, except that the veloper activity auxiliary developing agent P P of P1765811t The foregoing examples illustrate, by comparison, that ventlon are included in the acetonitrile that 1s spread on the 1 prints having low i i densities may be b. Overcoat layer of the negative- In some Cases a methanol tained by the employment of the oxazine and bisoxazine Solution the P1ecursor is p y Solutions of auxiliary developing agent precursors of the present infonowing compounds are employed: vention, which precursors yield substantially colorless,

Y Y Y ,7,8 hex hy alkalisoluble hydroxymethylaminomethylhydroquinones 1,5-di0Xa-3J-dialaaflthfflcene when treated with an alkali processing solution.

0 The most satisfactory auxiliary developers in dye-devel- HOCH CHg-N oper color image transfer systems has been hydroquinones, OH such as 4-methyl-phenyl hydroquinone. Such developers 2 2 \O/ arfeflless reslsttant t1? aerial OlildflllOlJ than corlnpioundz 0 1s 1nven ion. or exam e, a ace 0 1 r1 0 o 3,6 bismydmxyethyl 23,4559 hexahydm 3,6 dibenzyl 2,3,4,5,6,7 hexaliydro 1,8 51%;; 2,6-

1:8'dlOXa'3,6413Zaphenanthrene diazaphenathrene remains colorless when exposed to air.

However, an acetonitrile solution of 4-methylhydroqui- O 0 none turns yellow when exposed to air, indicating aerial NZOHWHZOH plzgggglon and reduced etfectiveness as an auxiliary dedimethyl 1 1 heXahydl'o The invention has been described in considerable detail di0Xa-3fi-fiialaphenanthffine with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

I claim:

1. A multilayered photographic product comprising a photosensitive element, which comprises a support layer, at least one light-sensitive silver halide emulsion layer and a dye developer which is both a silver halide developing agent and a dye contiguous to the silver halide of said silver halide emulsion layer, and incorporated in one of the layers of said photographic product a substantially colorless, auxiliary silver halide developing agent precursor selected from the group consisting of oxazines and bisoxazines capable of forming a substantially colorless, alkali-soluble hydroquinone.

2. A photographic product as defined in claim 1 wherein the auxiliary developing agent precursor is a compound of the formula:

III Ra R wherein R represents a group selected from the class consisting of a hydrogen atom, a lower alkyl group; a cycloalkyl group; and, an alkenyl group; R R and R each represents a hydrogen atom or, R and R or R and R when taken together, form an aminobismethylene group having the formula in which R represents any of the groups represented by R.

3. A photographic product according to claim 1 wherein the auxiliary silver halide developing agent precursor is a compound of the formula O- m @959 1 I111 wherein R and R each represents a group selected from the class consisting of a hydrogen atom, a lower alkyl group; a cycloalkyl group; and, an alkenyl group.

4. A photographic product according to claim 1 wherein the auxiliary silver halide developing agent precursor is incorporated into a layer of the photosensitive element.

5. A photographic product according to claim 1 where in the precursor is employed at a concentration in the range of between about 3 and about 500 milligrams per square foot.

6. A photographic product according to claim 1 wherein the photosensitive element comprises a plurality of lightsensitive layers sensitive to light of diiferent regions of the spectrum.

7. A multilayered photographic product comprising a photosensitive element, which comprises a support layer; at least one light-sensitive silver halide emulsion layer; a dye developer which is both a silver halide developing agent and a dye contiguous to the silver halide of said silver halide emulsion layer; and, incorporated in one of the layers of said photographic product, a substantially colorless, alkali-soluble auxiliary silver halide developing agent which is a hydroquinone containing at least one hydroxyalkylaminoalkyl group.

8. A photographic product according to claim 7 wherein the auxiliary developing agent is selected from the group consisting of a 2,3-bis[hydroxymethylaminomethyl] hydroquinone, a Z-hydroxymethylaminomethylhydroquinone, and a 2,5-bis[hydroxymethylaminomethyl]hydroquinone.

9. A photographic product according to claim 7 wherein: a dye developer reception layer is provided which is capable of being superposed on said photosensitive element; and, a rupturable container holding an alkaline processing solution and said auxiliary developing agent, positioned in said product as to be capable, upon being ruptured, of releasing said processing solution and said auxiliary developing agent for application to said superposed photosensitive element and reception layer.

10. In the processing of an exposed photosentive element comprising a support, at least one light-sensitive silver halide emulsion layer and a dye developer which is both a silver halide developing agent and a dye contiguous to the silver halide of said silver halide emulsion layer, said processing being etfected by treating said photosensitive element with an alkaline liquid, developing a latent image in the regions of exposure of said silver halide emulsion layer and thereby immobilizing said dye developer in said regions of exposure, dye developer in undeveloped regions diffusing irnagewise in register to a dye developer reception layer, the improvement which comprises initiating said processing in the presence of a substantially colorless, auxiliary silver halide developing agent precursor selected from the group consisting of oxazines and bisoxazines capable of forming substantially colorless, alkali-soluble hydroquinones in said alkaline liquid.

11. A process as defined in claim 10 wherein the precursor is a compound of the formula R2 l 69 1? 1'1, R

wherein R represents a group selected from the class consisting of a hydrogen atom, a lower alkyl group, a cycloalkyl group; an alkenyl group, R R and R each represents a hydrogen atom or R and R or R and R when taken together, form an aminobismethylene group having the formula in which R represents any of the groups represented by R.

12. A process as defined in claim 10 wherein the precursor is incorporated in a layer of the photosensitive element.

13. A process as defined in claim 10 wherein the precursor is present at a concentration of between about 3 and about 500 milligrams per square foot.

14. In the processing of an exposed photosensitive element comprising a support, at least one light-sensitive silver halide emulsion layer and a dye developer which is both a silver halide developing agent and a dye contiguous to the silver halide of said silver halide emulsion layer, said processing being effected by treating said photosensitive element with an alkaline liquid, developing a latent image in the regions of exposure of said silver halide emulsion layer and thereby immobilizing said dye developer in said regions of exposure, dye developer in undeveloped regions diffusing imagewise in register to a dye developer reception layer, the improvement which comprises effecting said processing in the presence of a substantially colorless, alkali-soluble auxiliary silver halide developing agent which is a hydroquinone containing at least one hydroxyalkylaminoalkyl group.

15. A process as defined in claim 14 wherein the auxiliary developing agent is selected from the group consisting of a 2,3-bis[hydroxymethylaminomethyl]hydroquinone; a 2-hydroxymethylaminomethyldroquinone; and a 2,5-bis[hydroxymethylaminomethyl]hydroquinone.

15 16. A process as defined in claim 14 wherein the auxiliary developing agent is present in the alkaline liquid which is employed to treat the photosensitive element.

References Cited UNITED STATES PATENTS 3,287,129 11/1966 Rees et a1. 9635 3,291,609 12/1966 Porter et a1. 9676 3,345,170 10/1967 Evans et a1. 9635 NORMAN G. TORCHIN, Primary Examiner A. T. SURO PICO, Assistant Examiner US. Cl. X.R. 9666 

